You are correct in that there is quite a lot of contention when it comes to the current structure of the international system. While the PRC undoubtedly has a lot of economic heft, the degree to which this actually impacts the "polarity" of the system is unclear. The USSR was not a great power merely because it had a lot of tanks; it was at least seen as a political hegemon that controlled critical territory that allowed it potential world domination. It also had a a foreign policy objective diametrically opposed to the US - leading non-US aligned states t...
That is absolutely true, but it remains to be seen if those attempts will hold up in the long run. There is a big difference between American power being in decline (but still dominant) and the world being multipolar. I would say that currently the derivative is <0 but American power is still vastly greater than any other country.
Of course the Chinese nuclear arsenal is enough in absolute terms to destroy a large segment of the US population (and an even greater share of GDP) but I would not say the same in practice. Contrary to the US and Russia, China... (read more)